Soft supramolecular materials

The existence of several energetically similar forms for the same compound is another typical feature of soft supramolecular materials. This property is a result of the weak linkage between building units and the variety of ways the units can assemble into a structure. A small change in external conditions can lead to another thermodynamically stable form, or. a little change in preparative conditions can lead to another kinetically stable product. The problem may show as polymorphism for forms having the same (polymorphs) overall composition, or pseudopolymorphism, where the components are present in different proportions, or as so-called supramolecular isomerism for forms having the same composition of the host framework. Water exemplifies such a structural... 

Examples of soft supramolecular materials that are "smart as they interact physicaily with the environment are available.More complicated are systems in... 

The behaviour and magnitude of the storage and loss moduli and yield stress as a function of applied stress or oscillatory frequency and concentration can be modelled mathematically and leads to conclusions about the structure of the material.3 For supramolecular gels, for example, their structure is not simple and may be described as cellular solids, fractal/colloidal systems or soft glassy materials. In order to be considered as gels (which are solid-like) the elastic modulus (O ) should be invariant with frequency up to a particular yield point, and should exceed G" by at least an order of magnitude (Figure 14.2). 

Lipids and fats, as soft condensed material in general, are very complex systems, not only in their static structures but also with respect to their kinetics of supramolecular formation. Hysteresis phenomena or supercooling can gravely complicate the task of defining the underlying structures and boundaries in a phase diagram (p. 334). 

Courlois J, Baroudi I, Nouvel N, Degrandi E, Pensec S, Ducouret G, Chaneac C, Bouteiller L, Creton C (2010) Supramolecular soft adhesive materials. Adv Funct Mater 20 (11) 1803-1811... 

As a powerful methodology to assemble various components into soft supramolecular organizations, the LbL assembly method shows continuous progresses in the fields of drug delivery under the supramolecular concept (Fig. 2.2.5). The LbL method has excellent versatility for the assembly of various kinds of substances [13]. This method covers a wide range of available materials including proteins, nucleic acids, saccharides, virus particles micelles, vesicles, LB films, and other lipid membranes as well as conventional polyelectrolytes, conductive polymers, inorganic nanomaterials, nanocarbons, and dye... 

Self-organization phenomena at nanoscale in materials science are mostly observed in soft matter component or supramolecular materials [81, 82] where some forces including electrostatic, short-range van der Waals, and dipolar usually stabilize the nanostructures. Sometimes, branched structures formed in metallic nanostructured... 

As a start to a tetralogy on dendrimers, the volumes Dendrimers and Den-drimers II have already appeared in print. This mini-series continues now with the latest volume Dendrimers III and will be completed by the fourth volume Dendrimers IV within the next few months. Volume III offers dendrimers based on novel design concepts leading to highly stiffened and shape persistent dendritic structures as well as to new families of rather soft and floppy dendrimers and focuses on new functional properties and materials aspects. As an example, the question of host-guest interactions with dendrimers, whose existence has been under intense debate for a long time, finds its final - and positive - answer in this volume. As a consequence, dendrimers clearly represent a subset of supramolecular chemistry. 

The kinds of structures adopted by these microorganisms as well as other mineral morphologies, are the subject of increasing study as chemists look at soft templated routes to nanoscale objects. Early work in the 1990s by a team at Mobile used supramolecular micelles, lamellae and bicontinuous phases4 formed by amphiphiles, to assemble inorganic materials, particularly silica and alumina. A range of new... 

---